Crystallographic and magnetic properties of CoCrxFe2-xO4 ferrite powders

The CoCrxFe2-xO4 (0.0 less than or equal to x less than or equal to 1.0) ferrite powders are fabricated by a sol-gel method. The crystallographic and magnetic properties of powders are investigated by X-ray diffraction (XRD), Mossbauer spectroscopy, scanning electron micrography (SEM) and vibrating sample magnetometer (VSM). The structures are spinel, and the lattice constants and the size of particle decrease with increasing Cr contents in CoCrxFe2-xO4. The Mossbauer spectra, consisted of two Zeeman sextets (0.0 less than or equal to x less than or equal to 0.6) due to Fe3+ ions at tetrahedral and octahedral sites, changed gradually to doublet (0.8 less than or equal to x less than or equal to 1.0) at room temperature. The variation of Mossbauer parameters has been discussed with the crystallographic and magnetic properties of powders. The magnetic hyperfine fields and the Neel temperature decrease with increasing Cr contents. The coercivity decreases fast but the saturation magnetization slowly decreases with increasing I in CoCrxFe2-xO4. (C) 2000 Elsevier Science B.V. All rights reserved.